library/src/main/java/com/datatorrent/lib/streamquery/condition/EqualValueCondition.java

/*
 * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datatorrent.lib.streamquery.condition;

import java.util.HashMap;
import java.util.Map;


/**
 * An implementation of condition on column equality. 
 * <p>
 * A valid row must have all key/value map in column name/value map.
 *
 * <b> Properties : </b> <br>
 *  <b> equalMap : </b> Column equal value map store.
 * @displayName: Equal Value Condition
 * @category: streamquery/condition
 * @tag: sql condition
 * @since 0.3.4
 */
public class EqualValueCondition extends Condition
{

  /**
   * Equal column map.
   */
  private HashMap<String, Object> equalMap = new HashMap<String, Object>();

  /**
   * Add column equal condition.
   */
  public void addEqualValue(String column, Object value)
  {
    equalMap.put(column, value);
  }

  /**
   * Check valid row.
   */
  @Override
  public boolean isValidRow(Map<String, Object> row)
  {
    // no conditions
    if (equalMap.size() == 0)
      return true;

    // compare each condition value
    for (Map.Entry<String, Object> entry : equalMap.entrySet()) {
      if (!row.containsKey(entry.getKey()))
        return false;
      Object value = row.get(entry.getKey());
      if (entry.getValue() == null) {
        if (value == null)
          return true;
        return false;
      }
      if (value == null)
        return false;
      if (!entry.getValue().equals(value))
        return false;
    }
    return true;
  }

  /**
   * check valid join, not implemented
   * 
   * @return false
   */
  @Override
  public boolean isValidJoin(Map<String, Object> row1, Map<String, Object> row2)
  {
    return false;
  }
}